q.5. which of the following statements is false?
a) matter is anything that has mass and takes up space.
b) elements cannot be chemically broken down into simpler substances.
c) elements are composed of atoms.
d) all pure substances are elements.
q.6. which of the following is a compound?
a) water b) aluminum foil
c) air d) salt water
q.7. which of the following statements is false about mixtures?
a) mixtures can be liquids, gases, and solids.
b) a mixture has a fixed chemical composition.
c) the substances retain their identities in a mixture.
d) mixture can be separated into simpler substances by physical process.
q.8. which diagram represents a mixture?
a)
b)
c)
d)

Question

Accepted Answer

# Q.5
# Brief Explanations:
- **a)** Matter is defined as anything with mass and volume (takes up space). This is a correct statement.
- **b)** Elements are the simplest form of matter that cannot be broken down chemically. This is correct.
- **c)** Elements are made up of atoms. For example, gold ($Au$) is made of gold atoms. This is correct.
- **d)** Pure substances include both elements (e.g., $O_2$) and compounds (e.g., $H_2O$). So, not all pure substances are elements. This is false.

# Answer:
d) All pure substances are elements.

# Q.6
# Brief Explanations:
- **a)** Water ($H_2O$) is a compound as it is made of two different elements ($H$ and $O$) chemically combined.
- **b)** Aluminum foil is an element ($Al$).
- **c)** Air is a mixture of gases like $N_2$, $O_2$, $CO_2$ etc.
- **d)** Salt - water is a mixture of salt ($NaCl$) and water ($H_2O$).

# Answer:
a) Water

# Q.7
# Brief Explanations:
- **a)** Mixtures can be in any state. For example, salt - water (liquid), air (gas), and an alloy like steel (solid). This is correct.
- **b)** A mixture has a variable chemical composition. For example, in salt - water, the amount of salt can vary. So, the statement “A mixture has a fixed chemical composition” is false.
- **c)** In a mixture, substances retain their identities. In air, $N_2$ and $O_2$ retain their properties. This is correct.
- **d)** Mixtures can be separated by physical processes. Salt - water can be separated by evaporation (water evaporates leaving salt). This is correct.

# Answer:
b) A mixture has a fixed chemical composition.

# Q.8
# Brief Explanations:
- A mixture contains different types of particles.
- **a)** Shows only one type of atom (assuming they are same - type atoms), so it is an element (not a mixture).
- **b)** Shows only one type of molecule (assuming they are same - type molecules), so it is a pure substance (either an element if it is a diatomic element like $O_2$ or a compound if it is a poly - atomic molecule like $H_2O$).
- **c)** Shows two different types of molecules. So, it represents a mixture.
- **d)** Shows only one type of molecule (assuming they are same - type molecules), so it is a pure substance.

# Answer:
c)

Sovi.AI - AI Math Tutor

QUESTION IMAGE

Question

Explanation:

Q.5

Answer:

Q.6